title: NMR R1 rho rotating-frame relaxation with weak radio frequency fields.
mesh_terms: D000818:Animals; D007611:Aprotinin / Q000737:chemistry*; D002417:Cattle; D008432:Mathematical Computing; D009587:Nitrogen Isotopes; D019906:Nuclear Magnetic Resonance, Biomolecular / Q000379:methods*; D025801:Ubiquitin / Q000737:chemistry*
chemical_list: D009587:Nitrogen Isotopes; D025801:Ubiquitin; D007611:Aprotinin